Way to be morbid.
It's been a while since I've seen Death Note, but if I remember correctly you could script out events for the person to act out leading up to their death. If that is indeed correct, here is what I would do:
1. Get a shit-tier service job, like fast food, gas station, etc., in the wealthiest neighborhood I could find, preferably populated by the kind of rich people who tend to be total assholes
2. Keep doing the job normally. Every time someone obviously rich is an asshole to me, I make a note of their face, as well as something to identify them (name on credit card, id card if buying cigs, license plate on car, etc.)
3. Go home, write their name in the death note, along with a script instructing the person to convert all of their personal assets to cash, put the cash in a duffel bag, leave the duffel bag in a location specified by me, and then kill themselves, probably in public and in a hilarious way.
4. Repeat process until I feel I have enough money to live comfortably for the rest of my life, or until L/Near/Whoever starts catching on
5. Put on mask, relinquish ownership of the Death Note to some stranger who doesn't know me. The fallout is their problem now.
I might have to fine-tune this plan since, like I said, I don't remember a lot of the specifics of the rules of the Death Note. However, this is the basic outline of what I would do.